1. Field of the Invention
The present invention relates to a remote control system for a vehicle door (s) which can automatically lock and unlock the door(s) of a vehicle in wireless communication and more particularly to a remote control system for a vehicle which can automatically lock the door(s) of a vehicle when a user (driver) who carries with him an electronic or entry key (with a portable transmitter/receiver) which includes an identification code assigned to the vehicle, walks away a first predetermined distance from the vehicle and automatically unlock the same when the user comes back to a second predetermined distance.
More particularly, the present invention relates to an improvement of the remote door lock controlling apparatus for a vehicle which is capable of inhibiting the automatically controlled locking and unlocking action of the door(s) of the vehicle either upon user""s request or in response to decrease to lower than a predetermined level of a voltage of a vehicle mounted battery.
2. Description of the Related Art
Lock/unlock remote-control systems for vehicle doors are known having a so-called, xe2x80x9cwelcome functionxe2x80x9d. In the systems, every user (driver) of a vehicle owns an entry key (with a portable transmitter/receiver) which upon receiving a response demand signal that is transmitted from a transmitter installed in the vehicle and is receivable within a predetermined range about the vehicle (which may be referred to as xe2x80x9chaving a predetermined communication areaxe2x80x9d hereinafter), can transmit a response signal carrying a unique identification code assigned in advance to each vehicle. When the user walks away from the predetermined range of the vehicle and its entry key is disabled to receive the response demand signal and thus to transmit back the response signal, the door of the vehicle is automatically locked. When the entry key moves into the predetermined range and its response demand signal is received by the transmitter/receiver which then responses thereto to send back a response signal, the door is automatically unlocked.
For example, some of such conventional xe2x80x9cwelcome functionxe2x80x9d based lock/unlock remote-control systems for vehicle doors are disclosed in Japanese Patent Laid-open Publications (Heisei)5-106376 and (Heisei)10-25939 in which a transmitter mounted on a vehicle is provided for intermittently transmitting a response demand signal having a predetermined communication area and, when receiving a signal responding to the response demand signal from an entry key which is carried by the user of a vehicle and moves into the predetermined communication area, examining whether the response signal is valid (regular) or not (welcome code examination). When the response signal has been examined to be valid, the door(s) of the vehicle is automatically unlocked. On the contrary, when the response signal is not valid or when the entry key stays out of the predetermined communication area and the vehicle-mounted transmitter receives no response signal, the door remains locked.
Accordingly, when the user of the vehicle carrying the entry key simply walks away from the predetermined range of the vehicle, the door of the vehicle can automatically be locked without paying any attention to or operating the entry key. When the user comes into the range, the door can automatically be unlocked. This requires no boresome actions of unlocking the door for riding the vehicle as well as contributes to the prevention of failing to lock door(s), and of vehicle theft.
The conventional systems have some advantages, particularly once the communication area is preset to a smaller size (for example, one meter in radius), the systematic locking of the door can easily be confirmed after getting off the vehicle, the power consumption for transmitting signals can be as small as not hostile to a battery, and the ID code (uniquely assigned to a vehicle) can hardly be intercepted by any other parties. The locking of the door may be easily confirmed by auditorily and visually perceiving the sound of a door locking mechanism and the shift of an inside door lock knob to the lock position.
Another conventional system disclosed in Japanese Patent Laid-open Publication (Heisei)10-153025 is provided in which a transmission antenna for detecting the approaching of an object into a middle-sized area around a vehicle is mounted on the vehicle in addition to an antenna for transmitting the response demand signal. Upon detecting the approaching of the object or a driver into the middle-sized area, the vehicle releases the response demand signal with a small-sized predetermined communication area and, when receiving a response signal to the response demand signal from the entry key of the right driver, unlock the door. Also, a second transmitting means having a greater communication area is provided for locking the door. The door is thus locked when the communication to the entry key with the second transmitting means is disabled.
In the conventional system, when the user who owns an entry key (for example, a driver who may be referred to as an xe2x80x9centry keyxe2x80x9d hereinafter) departs from the vehicle, the automatic lock/unlock system of doors is automatically turned on. Therefore, the response demand signal is continuously transmitted, even if the vehicle remains parked for a long period of time, or the voltage of the vehicle mounted batter is declined to a shortage level. This may result in disadvantages of no power in the battery during the parking period, disabling the user with the entry key to step in the vehicle and/or to start the engine of the vehicle. Particularly, after a long period of the parking, the risk of power shortage will be increased.
An apparatus disclosed in a drawing of Japanese Patent Laid-open Publication (Heisei)10-25939 permits an electronic (entry) key to be equipped with a manual switch but fails to describe any door lock/unlock action controlled manually with the electronic key.
It is an object of the present invention to provide a remote controlled door lock/unlock controlling apparatus which permits a user with an entry key, or a driver of a vehicle, to arbitrarily disable a door lock/unlock controlling action, known as a xe2x80x9cwelcome functionxe2x80x9d, of automatically locking and unlocking a door(s) of the vehicle in response to the presence or absence of a response signal which is transmitted from the entry key in response to a response demand signal released from the vehicle, in order to minimize the consumption of power of a battery during the parking.
In the first aspect of the present invention, a remote door lock controlling apparatus for a vehicle comprises, a transmitter mounted on the vehicle for transmitting a response demand signal receivable within a predetermined range the outside of the vehicle, a receiver mounted on the vehicle for receiving a response signal from a portable transmitter/receiver which sends back the response signal in response to reception of the respond demand signal, a controlling means for controlling at least one of locking and unlocking of the door(s) of the vehicle in response to the reception of the response signal at the vehicle mounted receiver, the improvement comprising a function stopping means for stopping the transmission of the response demand signal.
Accordingly, the owner of the entry key can selectively and arbitrarily disable a welcome function for controlling the locking and unlocking of the vehicle door in response to the detection of the portable transmitter/receiver or the entry key either approaching from far to the vehicle or departing from the vehicle, that is, stopping of transmitting the response demand signal from the vehicle mounted transmitter for the welcome function. When the vehicle battery may be nearly exhausted after a long period of the parking and the welcome function may fail to perform automatically unlocking the door, or the operating torque of a starter motor may be declined to a too low level to start the engine, the welcome function can temporarily be stopped to save the battery.
In the second aspect of the present invention, a remote door lock controlling apparatus for a vehicle further comprises avoltage detecting means for detecting decrease of a voltage of a battery mounted on the vehicle to lower than a predetermined level and producing a voltage drop signal, and the function stopping means stops the transmission of the response demand signal in response to the voltage drop signal.
Accordingly, when such decrease of the battery power may provide a lower output voltage to disable the control operations of the vehicle (particularly, the start up of the engine), the welcome function can automatically be stopped to save the battery power and sustain the minimum level of the control operations for the vehicle.
In a third aspect of the present invention, a remote door lock controlling apparatus for a vehicle further comprises a function stoppage directing means mounted at least one of the vehicle or the portable transmitter/receiver for producing a function stoppage signal when operated, and the function stopping means stops the transmission of the response demand signal in response to the function stoppage signal.
Accordingly, when the function control code transmitting means for directing the stopping and resuming the control functions is equipped in the portable transmitter/receiver or the entry key, even if the welcome function fails to be turned off by the user at the disembarkation or is desired to be turned off since the period of parking is to be extended, it can automatically be stopped thus permitting the user to be free from returning back to the vehicle to stop the welcome function and contributing to the improvement of the utility.
In a fourth aspect of the present invention, when the vehicle mounted receiver receives a manual control signal transmitted from the portable transmitter/receiver for door lock control, the controlling means carries out at least one of locking and unlocking the vehicle door(s) corresponding to the manual control signal received even if the transmission of the response demand signal is stopped.
Accordingly, the owner of the entry key or the portable transmitter/receiver can arbitrarily perform the door lock control for the vehicle at any time.